This invention relates to a medicament that inhibits the metastasis of cancer cells. More specifically, it relates to a medicament which comprises a monoclonal antibody specific to tenascin as the effective ingredient and works as a cancer metastasis inhibitor.
In the carcinogenesis of the epithelial cell, it is thought that the surrounding mesenchyme found around the epithelial cell (also known as the stroma), and in particular, the large molecular groups known as the extracellular matrix play a pivotal role. The extracellular matrix is an assembly that consists of various physiological substances such as collagens, and laminin and type IV collagen which compose the basement membrane, as well as tenascin, a glycoprotein with molecular weight of 190 and 250 kDa (Chiquet-Ehrismann, R., et al., Cell, 47, pp. 131-139, 1986).
Tenascin is found in the surrounding mesenchyme as a hexamer and is known to be expressed in a spatio-temporal manner in the processes of organogenesis, tissue regeneration, wound healing, and the proliferation or infiltration of cancer (Erickson, H. P., Annu.Rev. Cell Biol., 5, pp. 71-92, 1989; Sakakura, T., Tumor Matrix Biology, pp.101-129, CRC Press, 1995). With regards to the physiological function of tenascin, it is known to affect cell behavior in morphogenesis and tissue regeneration, including cell adhesion and detachment, the stimulation and inhibition of cell proliferation, as well as the activation of hemagglutination. Tenascin is ordinarily produced by fibroblasts, and it has been confirmed that cancer cells which are derived from the epithelium produce tenascin, the implication being that the production of tenascin in cancer cells is induced by a humoral factor deriving from the surrounding mesenchyme of cancer (Hiraiwa, N., et al., J. Cell. Science, 104, pp. 289-296, 1993). Furthermore, transforming growth factors (TGF xcex2) and epidermal growth factors (EGF) are known as substances which induce and activate tenascin (Chiquet-Ehrismann, R., et al., Cancer Res., 49, pp. 4322-4325, 1989; Sakai, T., et al., J. Cell. Physiol., 165, pp. 18-29, 1995).
Regarding the role of tenascin in the proliferation and metastasis of cancer cells, it has been proven through experimentation with a tenascin-deficient mouse that the production of tenascin in cancer cells is regulated by an inducing factor deriving from the surrounding mesenchyme cells (Kusaksabe, et al., Nyuugan Kiso Kenkyu, 5, pp. 41-45, 1996). It has also been demonstrated that the expression of this inducing factor is dependent upon tenascin, in other words, that tenascin itself acts on the surrounding mesenchymal cells of cancer and promotes the production of this inducing factor. In this manner, the interactions between tenascin and the said inducing substance can be considered a type of signal transduction.
As described above, it has been implied that tenascin is involved in the tumor growth and metastasis of cancer cells however, an anticancer drug which targets tenascin is yet to be developed. Although attempts are being made to utilize anti-tenascin monoclonal antibodies for purposes of cancer treatment, there has been no report so far of attempts to inhibit the metastasis of cancer cells by obstructing the function of tenascin.
An object of the present invention is to provide a metastasis inhibitor for cancer cells. More specifically, the object of the present invention is to provide a cancer metastasis inhibitor that targets tenascin, a substance that influences the metastasis and proliferation of cancer cells.
As a result of extensive research to solve the aforementioned object, the inventors discovered that anti-tenascin monoclonal antibodies obstruct the process in which cancer cells that entered the blood stream adhere and grow in other tissues, and thereby inhibit the metastasis of cancer cells in a highly effective manner. The invention was completed on the basis of this knowledge.
The present invention thus provides a cancer metastasis inhibitor comprising as an active ingredient an anti-tenascin monoclonal antibody. The medicament of the present invention can be given to all mammals including humans for the purpose of preventing cancer metastasis, for example, to the lungs. In addition, the present invention also provides an inhibitor of cancer cell adhesion comprising an anti-tenascin monoclonal antibody.
According to another aspect, there are provided a method for inhibiting cancer metastasis which comprises the step of administering an effective amount of an anti-tenascin monoclonal antibody to a mammal including human; and a method for inhibiting the adhesion of cancer cells which comprises the step of administering an effective amount of an anti-tenascin monoclonal antibody to a mammal including human. According to further aspect, a use of the anti-tenascin monoclonal antibody for the manufacture of the above-mentioned medicament.
The medicament of the present invention is characterized in that it comprises an anti-tenascin monoclonal antibody as an active ingredient and is used for the purpose of inhibiting cancer metastasis.
As for the anti-tenascin monoclonal antibody which is the active ingredient of the medicament of the present invention, it is preferred to use a monoclonal antibody that reacts specifically and substantially to tenascin. Among such monoclonal antibodies, it is desirable to use one that can obstruct the physiological functions of tenascin by bonding itself specifically to tenascin (i.e., a neutralizing antibody). Several varieties of tenascin isomers are known to exist, and a monoclonal antibody which reacts to any of these isomers, or alternatively, to multiple isomers can be used. The species of animal from which the monoclonal antibody will be developed are not particularly limited, and it is possible to use a facultative mammal that can be immunized by tenascin. Although there is no particular limitation to the subtype of monoclonal antibody, IgG2a xcexa, for example, is preferred.
In the case of administering the medicament of the present invention to humans, it is necessary to use, as the active ingredient, an anti-human tenascin monoclonal antibody that reacts to human derived tenascin. Such anti-human tenascin monoclonal antibodies may have cross-reactivity to non-human tenascin. For example, a monoclonal antibody that recognizes both mouse and human tenascin can be used as the active ingredient of the medicament of the present invention.
There is no particular limitation as to the epitope of a tenascin molecule that is recognized by the monoclonal antibody as being the active ingredient of the medicament of the present invention. For example, a monoclonal antibody which reacts to either one of the molecular domains of tenascin such as the EGF-like domain or fibronectin type III-like domain, or alternatively, to two or more domains can be used. Among these, though, the use of a monoclonal antibody which reacts to the EGF-like domain is preferred. Also, the monoclonal antibody may be modified with a single or more than two labeled compounds, or active ingredients for the treatment of cancer.
Examples of the anti-human tenascin monoclonal antibodies include, for example, 36-13-6 (A-D domain and fibronectin-like domain FN3-5; cross reacting to human and mouse; P. Shrestha, et al., International Journal of Oncology, 8, pp. 741-755, 1996; this antibody is also known as xe2x80x9cDEAR2xe2x80x9d), 7-13 (fibronectin type III-like domain; human-specific; P. Shrestha, et al., International Journal of Oncology, 8, pp. 741-755, 1996), 8C9 (EGF-like domain; human-specific; Oike, Y., et al., Int. J. Dev. Bio., 34, pp. 309-317, 1990; this antibody is also known as xe2x80x9cRCB1xe2x80x9d), 12-2-7 (EGF-like domain; cross reacting to human and mouse; Shrestha, P. et al., International Journal of Oncology, 8, pp.741-755, 1996), 3-58 (EGF-like domain; human-specific), and 3-6 (EGF-like domain; cross reacting to human and mouse; Koyama, Y., et al., Histochem. Cell Biol., 106, pp. 263-273, 1996; this antibody is also known as xe2x80x9cDEAR1xe2x80x9d). However, the monoclonal antibodies that can be used as the active ingredient of the medicament of the present invention are not limited to these examples (the information provided in brackets indicate the epitope of tenascin; these monoclonal antibodies all derive from rats). The tenascin used in developing anti-tenascin monoclonal antibodies can be easily obtained through the method described in literature (Oike, Y., et al., Int. J. Dev. Bio., 34, pp. 309-317, 1990).
The medicament of the present invention may preferably be administered parenterally. The form of preparation of the medicament of the present invention is not particularly limited; however, intravenous injections or intravenous drips are preferred. On occasion, intramuscular or hypodermic injections may be suitable. The medicament of the present invention may desirably be prepared in the form of a pharmaceutical composition comprising the active ingredient anti-tenascin monoclonal antibody, together with one or more pharmaceutical additives. More than two anti-tenascin monoclonal antibodies can be used in combination. The medicament of the present invention may be formulated together with one or more other ingredients effective for the therapeutic and/or preventive treatment of cancer, or the inhibition of metastasis.
The pharmaceutical additives used for the manufacture of the medicament of the present invention may be chosen by one of ordinary skilled in the art according to the type of the preparation. For example, stabilizers, solubilizing agents, buffering agents, pH modifiers, isotonicities, antiseptic substances or the like. The medicament can be manufactured as lyophilized injections or drip infusions. For the manufacture of such dry preparations, excipients may be used.
The medicament of the present invention can be administered to cancer hearing patients to prevent the metastasis of cancer. The medicament of the present invention functions to impede the process in which cells from cancer tissues enter the blood stream, adhere and grow in other tissues and form a metastasized lesion. There is no particular limitation to the type of metastasis, for example, to the lungs, liver, or bone. It is desirable that the dose is increased or decreased as necessary according to the purpose of administration, the conditions of the patient such as the weight and age, the type of the primary cancerous lesion, and severity of the cancer. In general, for an adult patient, it is desirable to administer a dose of approximately 1 to 1,000 mg either once a day or several times a day in divided doses. It is possible to administer intermittently at a rate of once in several days or several weeks.